MENLO PARK, Calif., March 14, 2012 /PRNewswire/ -- In
preclinical studies, researchers at SRI International and
Astraea Therapeutics have recently evaluated the role of a new drug
receptor target that shows promise for the treatment of drug
addiction.

This potential new drug target belongs to a class of receptors
called the nicotinic acetylcholine receptors (nAChRs). One subtype
of nAChRs, called alpha4beta2, is a well-known target for
nicotine's addictive effects and the therapeutic effect of the
smoking cessation drug varenicline. SRI researchers are now
studying another, lesser-known subtype, called alpha3beta4 nAChR,
which has recently shown to play a role in the addictive properties
of cocaine, morphine, and nicotine.

Using AT-1001, a highly selective alpha3beta4 compound developed
by Astraea Therapeutics, SRI researchers found that addiction
processes could be disrupted. In preliminary studies, AT-1001 also
reduced nicotine withdrawal symptoms such as anxiety.

Because addictive drugs act on the brain's "reward circuit,"
many people compulsively take them despite their harmful
consequences. Feelings of pleasure are caused by the release
of brain chemicals, or neurotransmitters, and their increased
activity in the brain reward circuit. The key
neurotransmitter in the reward circuit is dopamine, which produces
changes in addictive behavior. Researchers speculate that
disruption of the alpha3beta4 nAChR system using highly selective
drugs such as AT-1001 may interrupt this reward circuitry.

"Currently, there are no therapeutics approved to treat
addiction to stimulants such as cocaine, so it is intriguing to
find a promising drug receptor target and to see that AT-1001 can
indeed affect phenomena that are thought to be deeply tied to the
addictive nature of cocaine and other drugs of abuse," said Taline
Khroyan, Ph.D., Senior Behavioral Pharmacologist in SRI's Center
for Health Sciences.